feat: add metrics=timings to prefer header

CHANGELOG.md

@@ -23,6 +23,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
    + Shows the correct JSON format in the `hints` field
  - #3340, Log when the LISTEN channel gets a notification - @steve-chavez
  - #3184, Log full pg version to stderr on connection - @steve-chavez
+ - #3410, Add `metrics=timings` to Prefer header - @taimoorzaeem
 
 ### Fixed
 

src/PostgREST/ApiRequest/Preferences.hs

@@ -18,6 +18,7 @@ module PostgREST.ApiRequest.Preferences
   , PreferTransaction(..)
   , PreferTimezone(..)
   , PreferMaxAffected(..)
+  , PreferMetrics(..)
   , fromHeaders
   , shouldCount
   , prefAppliedHeader
@@ -44,6 +45,7 @@ import Protolude
 -- >>> deriving instance Show PreferHandling
 -- >>> deriving instance Show PreferTimezone
 -- >>> deriving instance Show PreferMaxAffected
+-- >>> deriving instance Show PreferMetrics
 -- >>> deriving instance Show Preferences
 
 -- | Preferences recognized by the application.
@@ -58,6 +60,7 @@ data Preferences
     , preferHandling       :: Maybe PreferHandling
     , preferTimezone       :: Maybe PreferTimezone
     , preferMaxAffected    :: Maybe PreferMaxAffected
+    , preferMetrics        :: Maybe PreferMetrics
     , invalidPrefs         :: [ByteString]
     }
 
@@ -67,7 +70,7 @@ data Preferences
 -- >>> let sc = S.fromList ["America/Los_Angeles"]
 --
 -- One header with comma-separated values can be used to set multiple preferences:
--- >>> pPrint $ fromHeaders True sc [("Prefer", "resolution=ignore-duplicates, count=exact, timezone=America/Los_Angeles, max-affected=100")]
+-- >>> pPrint $ fromHeaders True sc [("Prefer", "resolution=ignore-duplicates, count=exact, timezone=America/Los_Angeles, max-affected=100, metrics=timings")]
 -- Preferences
 --     { preferResolution = Just IgnoreDuplicates
 --     , preferRepresentation = Nothing
@@ -80,6 +83,7 @@ data Preferences
 --         ( PreferTimezone "America/Los_Angeles" )
 --     , preferMaxAffected = Just
 --         ( PreferMaxAffected 100 )
+--     , preferMetrics = Just Timings
 --     , invalidPrefs = []
 --     }
 --
@@ -97,6 +101,7 @@ data Preferences
 --     , preferTimezone = Nothing
 --     , preferMaxAffected = Just
 --         ( PreferMaxAffected 5999 )
+--     , preferMetrics = Nothing
 --     , invalidPrefs = [ "invalid" ]
 --     }
 --
@@ -129,6 +134,7 @@ data Preferences
 --     , preferHandling = Just Strict
 --     , preferTimezone = Nothing
 --     , preferMaxAffected = Nothing
+--     , preferMetrics = Nothing
 --     , invalidPrefs = [ "anything" ]
 --     }
 --
@@ -144,6 +150,7 @@ fromHeaders allowTxDbOverride acceptedTzNames headers =
     , preferHandling       = parsePrefs [Strict, Lenient]
     , preferTimezone       = if isTimezonePrefAccepted then PreferTimezone <$> timezonePref else Nothing
     , preferMaxAffected    = PreferMaxAffected <$> maxAffectedPref
+    , preferMetrics        = parsePrefs [Timings]
     , invalidPrefs         = filter isUnacceptable prefs
     }
   where
@@ -155,7 +162,8 @@ fromHeaders allowTxDbOverride acceptedTzNames headers =
                     mapToHeadVal [ExactCount, PlannedCount, EstimatedCount] ++
                     mapToHeadVal [Commit, Rollback] ++
                     mapToHeadVal [ApplyDefaults, ApplyNulls] ++
-                    mapToHeadVal [Strict, Lenient]
+                    mapToHeadVal [Strict, Lenient] ++
+                    mapToHeadVal [Timings]
 
     prefHeaders = filter ((==) HTTP.hPrefer . fst) headers
     prefs = fmap BS.strip . concatMap (BS.split ',' . snd) $ prefHeaders
@@ -179,7 +187,7 @@ fromHeaders allowTxDbOverride acceptedTzNames headers =
     prefMap = Map.fromList . fmap (\pref -> (toHeaderValue pref, pref))
 
 prefAppliedHeader :: Preferences -> Maybe HTTP.Header
-prefAppliedHeader Preferences {preferResolution, preferRepresentation, preferParameters, preferCount, preferTransaction, preferMissing, preferHandling, preferTimezone, preferMaxAffected } =
+prefAppliedHeader Preferences {preferResolution, preferRepresentation, preferParameters, preferCount, preferTransaction, preferMissing, preferHandling, preferTimezone, preferMaxAffected, preferMetrics } =
   if null prefsVals
     then Nothing
     else Just (HTTP.hPreferenceApplied, combined)
@@ -195,6 +203,7 @@ prefAppliedHeader Preferences {preferResolution, preferRepresentation, preferPar
       , toHeaderValue <$> preferHandling
       , toHeaderValue <$> preferTimezone
       , if preferHandling == Just Strict then toHeaderValue <$> preferMaxAffected else Nothing
+      , toHeaderValue <$> preferMetrics
       ]
 
 -- |
@@ -302,3 +311,12 @@ newtype PreferMaxAffected = PreferMaxAffected Int64
 
 instance ToHeaderValue PreferMaxAffected where
   toHeaderValue (PreferMaxAffected n) = "max-affected=" <> show n
+
+-- |
+-- Show Performance Metrics
+data PreferMetrics
+  = Timings -- show server timings for the request
+  deriving Eq
+
+instance ToHeaderValue PreferMetrics where
+  toHeaderValue Timings  = "metrics=timings"

src/PostgREST/App.hs

@@ -39,17 +39,20 @@ import qualified PostgREST.Query      as Query
 import qualified PostgREST.Response   as Response
 import qualified PostgREST.Unix       as Unix (installSignalHandlers)
 
-import PostgREST.ApiRequest           (ApiRequest (..))
-import PostgREST.AppState             (AppState)
-import PostgREST.Auth                 (AuthResult (..))
-import PostgREST.Config               (AppConfig (..), LogLevel (..))
-import PostgREST.Config.PgVersion     (PgVersion (..))
-import PostgREST.Error                (Error)
-import PostgREST.Observation          (Observation (..))
-import PostgREST.Response.Performance (ServerTiming (..),
-                                       serverTimingHeader)
-import PostgREST.SchemaCache          (SchemaCache (..))
-import PostgREST.Version              (docsVersion, prettyVersion)
+import PostgREST.ApiRequest             (ApiRequest (..))
+import PostgREST.ApiRequest.Preferences (PreferMetrics (..),
+                                         Preferences (..))
+import PostgREST.AppState               (AppState)
+import PostgREST.Auth                   (AuthResult (..))
+import PostgREST.Config                 (AppConfig (..),
+                                         LogLevel (..))
+import PostgREST.Config.PgVersion       (PgVersion (..))
+import PostgREST.Error                  (Error)
+import PostgREST.Observation            (Observation (..))
+import PostgREST.Response.Performance   (ServerTiming (..),
+                                         serverTimingHeader)
+import PostgREST.SchemaCache            (SchemaCache (..))
+import PostgREST.Version                (docsVersion, prettyVersion)
 
 import qualified Data.ByteString.Char8 as BS
 import qualified Data.List             as L
@@ -141,27 +144,29 @@ postgrestResponse appState conf@AppConfig{..} maybeSchemaCache pgVer authResult@
 
   body <- lift $ Wai.strictRequestBody req
 
-  let jwtTime = if configServerTimingEnabled then Auth.getJwtDur req else Nothing
+-- the preference metrics=timings cant be used before it is parsed, hence
+-- parseTime will be calculated for all requests
+  (parseTime, apiReq@ApiRequest{..}) <- withTiming True $ liftEither . mapLeft Error.ApiRequestError $ ApiRequest.userApiRequest conf req body sCache
+  let timingsPref = preferMetrics iPreferences == Just Timings
+  (planTime, plan)                   <- withTiming timingsPref $ liftEither $ Plan.actionPlan iAction conf apiReq sCache
+  (queryTime, queryResult)           <- withTiming timingsPref $ Query.runQuery appState conf authResult apiReq plan sCache pgVer (Just authRole /= configDbAnonRole)
+  (respTime, resp)                   <- withTiming timingsPref $ liftEither $ Response.actionResponse queryResult apiReq (T.decodeUtf8 prettyVersion, docsVersion) conf sCache iSchema iNegotiatedByProfile
 
-  (parseTime, apiReq@ApiRequest{..}) <- withTiming $ liftEither . mapLeft Error.ApiRequestError $ ApiRequest.userApiRequest conf req body sCache
-  (planTime, plan)                   <- withTiming $ liftEither $ Plan.actionPlan iAction conf apiReq sCache
-  (queryTime, queryResult)           <- withTiming $ Query.runQuery appState conf authResult apiReq plan sCache pgVer (Just authRole /= configDbAnonRole)
-  (respTime, resp)                   <- withTiming $ liftEither $ Response.actionResponse queryResult apiReq (T.decodeUtf8 prettyVersion, docsVersion) conf sCache iSchema iNegotiatedByProfile
+  let jwtTime = if timingsPref then Auth.getJwtDur req else Nothing
 
-  return $ toWaiResponse (ServerTiming jwtTime parseTime planTime queryTime respTime) resp
+  return $ toWaiResponse timingsPref (ServerTiming jwtTime parseTime planTime queryTime respTime) resp
 
   where
-    toWaiResponse :: ServerTiming -> Response.PgrstResponse -> Wai.Response
-    toWaiResponse timing (Response.PgrstResponse st hdrs bod) = Wai.responseLBS st (hdrs ++ ([serverTimingHeader timing | configServerTimingEnabled])) bod
-
-    withTiming :: Handler IO a -> Handler IO (Maybe Double, a)
-    withTiming f = if configServerTimingEnabled
-        then do
-          (t, r) <- timeItT f
-          pure (Just t, r)
-        else do
-          r <- f
-          pure (Nothing, r)
+    toWaiResponse :: Bool -> ServerTiming -> Response.PgrstResponse -> Wai.Response
+    toWaiResponse includeTimings timing (Response.PgrstResponse st hdrs bod) = Wai.responseLBS st (hdrs ++ ([serverTimingHeader timing | includeTimings])) bod
+
+    withTiming :: Bool -> Handler IO a -> Handler IO (Maybe Double, a)
+    withTiming True f = do
+                        (t, r) <- timeItT f
+                        pure (Just t, r)
+    withTiming False f = do
+                        r <- f
+                        pure (Nothing, r)
 
 traceHeaderMiddleware :: AppState -> Wai.Middleware
 traceHeaderMiddleware appState app req respond = do

src/PostgREST/Auth.hs

@@ -107,25 +107,16 @@ middleware appState app req respond = do
   let token  = fromMaybe "" $ Wai.extractBearerAuth =<< lookup HTTP.hAuthorization (Wai.requestHeaders req)
       parseJwt = runExceptT $ parseToken conf (LBS.fromStrict token) time >>= parseClaims conf
 
--- If DbPlanEnabled       -> calculate JWT validation time
--- If JwtCacheMaxLifetime -> cache JWT validation result
-  req' <- case (configServerTimingEnabled conf, configJwtCacheMaxLifetime conf) of
-    (True, 0)            -> do
+-- If JwtCacheMaxLifetime      -> cache JWT validation result
+  req' <- case configJwtCacheMaxLifetime conf of
+      0            -> do
           (dur, authResult) <- timeItT parseJwt
           return $ req { Wai.vault = Wai.vault req & Vault.insert authResultKey authResult & Vault.insert jwtDurKey dur }
 
-    (True, maxLifetime)  -> do
+      maxLifetime  -> do
           (dur, authResult) <- timeItT $ getJWTFromCache appState token maxLifetime parseJwt time
           return $ req { Wai.vault = Wai.vault req & Vault.insert authResultKey authResult & Vault.insert jwtDurKey dur }
 
-    (False, 0)           -> do
-          authResult <- parseJwt
-          return $ req { Wai.vault = Wai.vault req & Vault.insert authResultKey authResult }
-
-    (False, maxLifetime) -> do
-          authResult <- getJWTFromCache appState token maxLifetime parseJwt time
-          return $ req { Wai.vault = Wai.vault req & Vault.insert authResultKey authResult }
-
   app req' respond
 
 -- | Used to retrieve and insert JWT to JWT Cache

src/PostgREST/Response.hs

@@ -69,7 +69,7 @@ actionResponse (DbCrudResult WrappedReadPlan{wrMedia, wrHdrsOnly=headersOnly, cr
     RSStandard{..} -> do
       let
         (status, contentRange) = RangeQuery.rangeStatusHeader iTopLevelRange rsQueryTotal rsTableTotal
-        prefHeader = maybeToList . prefAppliedHeader $ Preferences Nothing Nothing Nothing preferCount preferTransaction Nothing preferHandling preferTimezone Nothing []
+        prefHeader = maybeToList . prefAppliedHeader $ Preferences Nothing Nothing Nothing preferCount preferTransaction Nothing preferHandling preferTimezone Nothing preferMetrics []
         headers =
           [ contentRange
           , ( "Content-Location"
@@ -99,7 +99,7 @@ actionResponse (DbCrudResult MutateReadPlan{mrMutation=MutationCreate, mrMutateP
       pkCols = case mrMutatePlan of { Insert{insPkCols} -> insPkCols; _ -> mempty;}
       prefHeader = prefAppliedHeader $
         Preferences (if null pkCols && isNothing (qsOnConflict iQueryParams) then Nothing else preferResolution)
-        preferRepresentation Nothing preferCount preferTransaction preferMissing preferHandling preferTimezone Nothing []
+        preferRepresentation Nothing preferCount preferTransaction preferMissing preferHandling preferTimezone Nothing preferMetrics []
       headers =
         catMaybes
           [ if null rsLocation then
@@ -139,7 +139,7 @@ actionResponse (DbCrudResult MutateReadPlan{mrMutation=MutationUpdate, mrMedia}
       contentRangeHeader =
         Just . RangeQuery.contentRangeH 0 (rsQueryTotal - 1) $
           if shouldCount preferCount then Just rsQueryTotal else Nothing
-      prefHeader = prefAppliedHeader $ Preferences Nothing preferRepresentation Nothing preferCount preferTransaction preferMissing preferHandling preferTimezone preferMaxAffected []
+      prefHeader = prefAppliedHeader $ Preferences Nothing preferRepresentation Nothing preferCount preferTransaction preferMissing preferHandling preferTimezone preferMaxAffected preferMetrics []
       headers = catMaybes [contentRangeHeader, prefHeader]
 
     let (status, headers', body) =
@@ -158,7 +158,7 @@ actionResponse (DbCrudResult MutateReadPlan{mrMutation=MutationUpdate, mrMedia}
 actionResponse (DbCrudResult MutateReadPlan{mrMutation=MutationSingleUpsert, mrMedia} resultSet) ctxApiRequest@ApiRequest{iPreferences=Preferences{..}} _ _ _ _ _ = case resultSet of
   RSStandard {..} -> do
     let
-      prefHeader = maybeToList . prefAppliedHeader $ Preferences Nothing preferRepresentation Nothing preferCount preferTransaction Nothing preferHandling preferTimezone Nothing []
+      prefHeader = maybeToList . prefAppliedHeader $ Preferences Nothing preferRepresentation Nothing preferCount preferTransaction Nothing preferHandling preferTimezone Nothing preferMetrics []
       cTHeader = contentTypeHeaders mrMedia ctxApiRequest
 
     let isInsertIfGTZero i = if i > 0 then HTTP.status201 else HTTP.status200
@@ -181,7 +181,7 @@ actionResponse (DbCrudResult MutateReadPlan{mrMutation=MutationDelete, mrMedia}
       contentRangeHeader =
         RangeQuery.contentRangeH 1 0 $
           if shouldCount preferCount then Just rsQueryTotal else Nothing
-      prefHeader = maybeToList . prefAppliedHeader $ Preferences Nothing preferRepresentation Nothing preferCount preferTransaction Nothing preferHandling preferTimezone preferMaxAffected []
+      prefHeader = maybeToList . prefAppliedHeader $ Preferences Nothing preferRepresentation Nothing preferCount preferTransaction Nothing preferHandling preferTimezone preferMaxAffected preferMetrics []
       headers = contentRangeHeader : prefHeader
 
     let (status, headers', body) =
@@ -206,7 +206,7 @@ actionResponse (DbCallResult CallReadPlan{crMedia, crInvMthd=invMethod, crProc=p
         then Error.errorPayload $ Error.ApiRequestError $ ApiRequestTypes.InvalidRange
           $ ApiRequestTypes.OutOfBounds (show $ RangeQuery.rangeOffset iTopLevelRange) (maybe "0" show rsTableTotal)
         else LBS.fromStrict rsBody
-      prefHeader = maybeToList . prefAppliedHeader $ Preferences Nothing Nothing preferParameters preferCount preferTransaction Nothing preferHandling preferTimezone preferMaxAffected []
+      prefHeader = maybeToList . prefAppliedHeader $ Preferences Nothing Nothing preferParameters preferCount preferTransaction Nothing preferHandling preferTimezone preferMaxAffected preferMetrics []
       headers = contentRange : prefHeader
 
     let (status', headers', body) =

test/io/test_big_schema.py

@@ -15,17 +15,18 @@ def test_requests_wait_for_schema_cache_reload(defaultenv):
         "PGRST_DB_SCHEMAS": "apflora",
         "PGRST_DB_POOL": "2",
         "PGRST_DB_ANON_ROLE": "postgrest_test_anonymous",
-        "PGRST_SERVER_TIMING_ENABLED": "true",
     }
 
+    headers = {'Prefer': 'metrics=timings'}
+
     with run(env=env, wait_max_seconds=30) as postgrest:
         # reload the schema cache
         response = postgrest.session.get("/rpc/notify_pgrst")
         assert response.status_code == 204
 
         postgrest.wait_until_scache_starts_loading()
 
-        response = postgrest.session.get("/tpopmassn?select=*,tpop(*)")
+        response = postgrest.session.get("/tpopmassn?select=*,tpop(*)", headers=headers)
         assert response.status_code == 200
 
         plan_dur = parse_server_timings_header(response.headers["Server-Timing"])[

test/io/test_io.py

@@ -1174,7 +1174,6 @@ def test_server_timing_jwt_should_decrease_on_subsequent_requests(defaultenv):
 
     env = {
         **defaultenv,
-        "PGRST_SERVER_TIMING_ENABLED": "true",
         "PGRST_JWT_CACHE_MAX_LIFETIME": "86400",
         "PGRST_JWT_SECRET": "@/dev/stdin",
         "PGRST_DB_CONFIG": "false",
@@ -1189,6 +1188,7 @@ def test_server_timing_jwt_should_decrease_on_subsequent_requests(defaultenv):
         },
         SECRET,
     )
+    headers["Prefer"] = "metrics=timings"
 
     with run(stdin=SECRET.encode(), env=env) as postgrest:
         first_timings = postgrest.session.get("/authors_only", headers=headers).headers[
@@ -1234,13 +1234,13 @@ def test_server_timing_jwt_should_not_decrease_when_caching_disabled(defaultenv)
 
     env = {
         **defaultenv,
-        "PGRST_SERVER_TIMING_ENABLED": "true",
         "PGRST_JWT_CACHE_MAX_LIFETIME": "0",  # cache disabled
         "PGRST_JWT_SECRET": "@/dev/stdin",
         "PGRST_DB_CONFIG": "false",
     }
 
     headers = jwtauthheader({"role": "postgrest_test_author"}, SECRET)
+    headers["Prefer"] = "metrics=timings"
 
     with run(stdin=SECRET.encode(), env=env) as postgrest:
         warmup_req = postgrest.session.get("/authors_only", headers=headers)
@@ -1264,13 +1264,13 @@ def test_jwt_cache_with_no_exp_claim(defaultenv):
 
     env = {
         **defaultenv,
-        "PGRST_SERVER_TIMING_ENABLED": "true",
         "PGRST_JWT_CACHE_MAX_LIFETIME": "86400",
         "PGRST_JWT_SECRET": "@/dev/stdin",
         "PGRST_DB_CONFIG": "false",
     }
 
     headers = jwtauthheader({"role": "postgrest_test_author"}, SECRET)  # no exp
+    headers["Prefer"] = "metrics=timings"
 
     with run(stdin=SECRET.encode(), env=env) as postgrest:
         first_timings = postgrest.session.get("/authors_only", headers=headers).headers[